Concrete-mixer.



E. WIET.

.- CONCRETE MIXER.

APPLICATION FILED OCT. 2|. 1913.

Patented Mar. 21, 1916.

A INVENTOR.

EUGENE WIET, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR TO PARROT-T & 00., 0F

\ SAN FRANCISCO, CALIFORNIA, A CORPORATION'OF CALIFORNIA.

CONCRETE-MIXER.

Specification of Letters Patent.

Patented Mar. 21, 1916.

Application filed October 21, 1913. Serial No. 796,429.

cisco, county of San Francisco, and Stateof California, have invented certain new and useful Improvements in Concrete- Mixers; and I do hereby declare the following to be a full, clear, and exact description of the said invention, such as will enable others skilled in the art to which it most nearly appertains to make, use, and practise the same. 4

This invention relates to improvements in concrete mixers and more particularly to that class known as hot mixers, for mixing and combining crushed stone and the like with bituminous rock, asphaltum, tar and other forms and combinations of material requiring heat treatment during the period of mixing.

Objects.Among the objects of this invention are: to provide means for introducing heat, at the desired temperature, into concretev mixersduring the period of inix-' ing or agitation; to provide a heating or combustion chamber adapted to be com bined with the conventional type of rotary concrete mixer, without altering its mechanism or mode of operation, wherebyit may be used as a hot mixer for asphaltic compounds, or as a wet, or dry mixer for cement concrete; to provide a pivotal mounting for the heating chamber, whereby it may be readily swung into and out of connection with the mixer, while the latter is charging 0r discharging; and of such constru'ctionthat it may be easily adjusted to work with most of the present types of mixers.

The many bituminous or plastic paving specifications vary greatly, as to the con-* stituents, proportions etc.; but certain average temperatures within the mixers are which is merely a matter of proper fuel I and operated, in accordance with this invention The invention possesses, other advantaproper coalescence;

required to cause the with tar concrete 200 to 250 degrees F.; with asphaltic concretef300 to 350idegrees F.;

regulation in a heater constructed geous' features that with the foregoing will be set forth at length in the following description, wherein I shall outline in full that form of the invention selected for illustration in the drawings, accompanying and forming part of the present specification. The novelty of the invention will be included in the claims succeeding said description. From this it is apparent, that I do not restrict myself to the disclosures made by said drawings and description, as I may adopt many variations within the scope of my invention expressed in said claims.

The mostcommon type of mixer includes.

a' rotatable drum tapered laterally to a re- I stricted charging opening on one side, and a similar discharging opening on the other side of the center line, provided thereat with an annular spur gear, enmeshed with a. driving pinion. A batch of the proper proportions of components is introduced into the drum through the charging opening, and is thoroughly mixed by the revolution of the drum, that is internally provided.

with baffle or mixing plates. During this mixing period the proper volume of heat is introduced into the drum, preferably through the charging opening, to cause the heating of the crushed stone, and the proper melting of the bituminous matter, to "cause a proper coalescence of the particles into a concrete plastic mass. This mass is discharged from the drum through the discharge opening, preferably by tilting the drum, or by introducing an inclined chute, into which the concrete will be dripped by the rotation of the drum. The use of the chute is usually confined to straight cylinhaving central openings in the heads.

In the drawings: Figure 1 is a side elevation of a heating mechanism constructed in accordance with this invention, and applied to a concrete mixing machine diagrammatically illustrated. Fig. 2 is a plan view from above of the heating mechanism disclosing its construction, and its relation to themixing drum, fragmentarily illustrated in dotted lines.

By pivoting the heater in the manner effect with the fire box.

shown the heat can be discharged into the mixer, or readily withdrawn, irrespective of the particular type of the mixer, whether tapered, cylindrical, or any other of the well known shapes, and rotating in the horizontal or vertical plane; or in stationary drums provided with mixing or agitating means.

0 nstructi0n.In detail, the construction of this invention as illustrated, includes the pivotal base 1, resting upon the cross beams 2-2, attached to the main frame of the mixer. This base is provided with the socket 3, preferably conical to receive the similarly shaped pivot 4, rotatable therein. The socket and the pivot are respectively provided with the chafing flanges 5 and 6, upon which the supported weight rests, to prevent thejamming of the pivot in the socket. v

The pivot is preferably cast integral with the supporting yoke 7, provided with the open bearings 88, to receive the trunnions 9-9, of the brackets l0-10 attached to the sides of the fire box 11, which is thus supported by the trunnions.

The fire box includes a hollow combustion chamber, lined with fire brick, or a proper heat resistant, into which the desired fuel is introduced for combustion. In the present instance the fire box is provided with a lower door 12, adapted to receive the fuel oil burner 13, connected by the pipe 14, with the source of supply. The structural details of the fire box will vary with the type of fuel to be consumed. To insure perfect combustion the flame is retained as long as desirable in the combustion chamber by properly placing the stack or outlet 15, preferably on the same end as the burner, to compel the flame to recross the combustion chamber before escaping, giving a reverberatory is attached to the outlet 15, and the connectmg pipe 17, this pipe rests within the'saddle's 1818, provided on the cast heads 19-19 of the fire box; making a very compact and I. rigid structure, desirable in any portable The mixer includes the rotatable, or fixed drum 20, within which the concrete is mixed. In the present instance, the conventional tapered, batch mixing, tilting drum is diagrammatically illustrated in the drawings. This drum is adapted to be rotated by the en glne 21, receiving its energy from the boiler 22, and suitably geared to the mixer. The

whole oufit is mounted upon the main frame 23, provided with the wheels 24, for ready transportation.

' The conducting pipe 17 is provided with the elbow 25, having the annular flange 26, attached thereto, and adapted to close the openin when t e end of the conducting pipe is in- The return bend 16- in the end of the mixing drum,

serted within the drum,see Fig. 2-. After the drum is duly charged, the end of the conducting pipe is inserted therein, the drum started rotating, and the burner turned on, to throw the heat generated in the fire box, through the conducting pipe and into the mixing drum, to act upon its agitated contents.

The peculiar double pivoting of the fire box permits it to swing outward on the horizontal plane on the vertical pivot 4; or vertically upon the horizontal trunnions 99. Either'one or both actions may be taken ad vantage of in disconnecting the fire box from the mixing drum, during the charging or discharging periods. If oil fuel is used the burner can be connected by flexible attachment to the source of supply, or the fire door 12, can be of such shape that it will allow suflicient play for the burner in the operation' of swinging the fire box.

To create a forced draft through the conducting pipe, the return bend may be provided with the opening, as at 27 for the introduction of a jet of steam, or compressed air through the'nozzle 28, fed from the boiler 22, or an air compressor. The introduction of steam in this manner increases the volume of heat by forced draft, and raises the temperature by the liberation of nascent oxygen as is well known in the addition of steam to combustion.

Since this outfit must be transported over rough pavements, and is subjected to rough handling generally, it has proven advantageous to interpose the buffer springs 29-29, between the main frame and the'fire box, to protect the usually brittle lining of the combustion chamber from the jolting and jarring of transportation, liable to dislodge it.

Having thus fully described this invention, what is claimed and desired to secure by Letters Patent is:

. 1. In combination with a mixer having a supporting frame; a fire box having a connecting pipe leading to said mixer, and horizontally pivoted in a supporting yoke vertically pivoted on said frame.

2. In combination with a mixer having a supporting frame; a base having a vertical socket; buffer springs interposed between said base and said frame; a yoke having a pivot engaging said socket; a fire box having orizontal trunnions engaging said yoke; and a connecting pipe leading from said fire box to said mixer.

3. In combination with a mixer having a supporting'frame; a fire box having horizontal trunnions; a yoke engaging said trunnions and vertically pivoted on said frame;

a-fuel burner in the front of said firebox;

4. In combination with a supporting frame; a mixer and a steam generator mounted on said frame; a fire box horizontally pivoted on a Vertical swivel on said 5 frame; a connecting pipe leading from said heater to the mixer; and a pipe leading from said generator to said connecting pipe.

In testimonywhereof, I have hereunto set I my hand this tenth day of October, 1913.

EUGENE WIET.

Witnesses BALDWIN VALE,

D. O. BOYLE. 

